Nitrogen demand and agro-environmental efficiency in Brazilian cereal production.

This paper aims to analyze the main factors that explain the demand for synthetic nitrogen fertilizers in Brazil, as well as the efficiency of their use. In addition, the research sought to relate the use of fertilizers with nitrous oxide (N2O) emissions. Demand was estimated using the two-stage least squares method (2SLS). Nitrogen use efficiency (NUE) was calculated using an agri-environmental index. The results indicated that demand of nitrogen fertilizers is positively affected by the price of cereal, cereal production and the number of fertilizers used in the past harvest. The calculated NUE presented an average value of 53% in the 1994-2018 period, indicating inefficient use of N. Emissions from nitrogen fertilization grew 59% for the same period. The increasing and / or inadequate rates of fertilizer use have resulted in agro-environmental inefficiency, that is, a decrease in NUE and an increase in N2O emissions. Public policies that guarantee more agricultural technical assistance and rational alternative forms of nitrogen use could contribute to optimizing the synthetic doses applied in production, minimizing adverse environmental effects without generating economic losses to farmers and Brazilian agricultural production.